Improvement in screw-propellers



E. 'A. HEATH. Screw-Propeller.

No. 218,438. Patented Aug. 12,1879.

V UNITED STATES PATENT OEEIoE.

EUGENE A. HEATH, on NEW YORK, N. Y.

,- lMPROVEME NT IN SCREW-PROPELLERS.

Specification forming part of Letters Patent No. 218,438, dated August12, 1879; application filed May 9, 1878.

To all whom it may concern Be it known that I, EUGENE A. HEATH, of thecity, county, and State of New York, have invented certain new anduseful Improvements in Screw-Propellers, of which the following is aspecification.

This invention relates to that class of devices for propelling vesselsknown as screwpropellers, which, as commonly used, consist of a seriesor set of four blades of peculiar shape and form, these blades, in theirrapid revolutions and action, possessing two powers, technically termedthe inclined plane and the lever, which blades, acting upon the body of.the water in a similar manner as a threaded screw in a nut, give thepropelling power.

The present invention consists in the novel application to thewell-known and conventional form of screw-propeller blades of a seriesof channels or flutes, such channels being cut on acute angles into andretiring from the face of the blades. They are preferably cut on curvedlines, and they may be more or less in number, and be convoluted andoverlie each other. The location of these channels upon the impingingface of the blades and their wedge shape are such as to give anincreased gripe upon the body of water, thereby increasing thepropelling power of the blades.

As an adjunct to' such channels or flutes, a series of perforations oropenings is made through the blades, in the base of the channels orbetween several of them, this for the purpose of permitting some of thewater to pass through to the rear of the blades, which action willresult in destroying any vacuum or partial vacuum that may form behindthe rapidly-revolving blades, thereby causing the blades to operate in asolid body of water instead of a mass of foam-all of which improvements,together with the application and operation thereof, will be hereinafterfully set forth and pointed out in detail.

In the drawings, which form an essential part of this specification,Figure l is a front elevation of a screw-propeller in which my inventionis fully embodied. Fig. 2 is a side elevation of the same, one of theblades being shown in section; and Fig. 3 is a modification thereof.

The same reference-letters marked on the various figures of the drawingswill locate and point out corresponding parts.

A B (J D represent the several blades of the propeller, which aremounted upon the shaft E. These blades may be cast separately andafterward attached to the hub, or the hub and blades may be cast as aunit, as mechanical skill may deem best.

a. b c d designate a series of channels or flutes formed in the body ofthe blades. They are retired from the face of the blades to the rear onacute angles, as plainly shown in blade B in Fig. 2, this formationgiving them a wedge shape. They are also preferably formed on the lineof a circle, as shown in Fig. 1, each circle being drawn from the samecenter, this for the purpose of securing a gradual and easy action onthe water, both in the action of griping and releasing it.

c, 0 and c in blades A B D represent a series of elongated slots cutthrough the blades, and located in between the various channels, or aportion of them, or from the base thereof, such openings being of thesame size on the front and rear of the blades, as will be seen in thedrawings. In some cases a series of straight holes, f, may be drilledthrough the blades, as shown on blade 0.

The modifications shown in Fig. 3 are necessarily but variations fromthe form of the channels shown in Fig. 1; and it is obvious that thenumber of the channels, flutes, or grooves, and the number of slots orholes, and their size, formed in the blades, may be varied to suitcircumstances.

In some cases angle-iron may be successfully riveted upon the face ofthe blades, giving an increased gripe upon the water; in other casescorresponding channels may be formed upon the rear face of the blades;but I prefer the formation first described.

The object aimed at in this invention is twofold-first, to increase thegripe of the blades upon the water, and, second, in connectiontherewith, to effectually prevent the formation of the vacuum or partialvacuum that now exists in the use of the common form of screwwithperforations or elongated holes opening propellers. from the basesthereof to the rear faces of the I claim as my invention blades,substantially as and for the purposes A screw-propeller wheel theseveral blades as shown and set forth.

of which are provided with a series of wedge- EUGENE A. HEATH.

shaped recesses, radiating from the hub and Witnesses:

retired at an angle from and below the faces A. L. MUNSON,

of the blades, such recesses being provided E. G. WARD.

